Apparatus for texturing asbestoscement sheets



Nov. 7, 1950 w. 1 NELSON 2,529,175

APPARATUS FOR TEXTURING AsBEsTos-CEMENT SHEETS Filed March 9, 1946 6 Sheets-Sheet 1 FIT-l 11i-H li.; l, l I 'l .1,5 m; Q jehz l E .6'.

Nov. 7, 1950 w. NELSON APPARATUS FOR TEXTURING ASBESTOS-CEMENT SHEETS 6 Sheets-Sheet 2 Filed March 9, 1946 Nov. 7, 1950 w. L.. NELSON 2,529,175

APPARATUS FOR TEXTURING AsBEsTos-CEMENT SHEETS Filed March 9, 1946 6 Sheets-Sheet 3 Nov. 7, 1950 w. NELSON v APPARATUS FOR TEXTURING ASBESTOS-CEMENT SHEETS Filed March 9, 1948 6 Sheets-Sheet 4 lil Nov. 7, 1950 w. l. NELSON 2,529,175

APPARATUS FOR GTEXTURING ASBESTOS-CEIENT SHEETS Filed llarch 9, 1946 6 Sheets-Sheet 5 @y/a f: MZ

Nov. 7, 1950 w. 1 NELSON 2,529,175

APPARATUS FOR TEXTURING ASBESTOS-CEIENT SHEETS MWh/@WWW /9 lf2/607' @le 29 Ara rfa/41 Patented Nov. 7, 19450 tiiiii'l' STATES PATENT OFFICE APPARATUS FOR TEXTURING ASBESTOS- GEMENT SHEETS Claims. Ti

The present invention relates to an apparatus for the texturing of asbestos-cement sheets, such as are commonly used for siding and rooing.

However, while the apparatus is primarily designed for that purpose, it will become evident that other plastic sheet material may be textured or otherwise ornamented by the same kind of apparatus.

Brcadly speaking, therefore, it may properly be said that the present invention relates to a suitable apparatus for carrying out the method.

In many fields, particularly that in which it is desired to make textured finishes on wet formed asbestos-cement sheets, grave operating diiculties, as well as frequently unsatisfactory results, are encountered when a die is pressed down- Wardly against the wet sheet. The pressures and apparatus weights involved in forming textured finishes on material such as asbestos-cement sheets are such as inevitably to introduce operating diiiiculties. The press breakage has been exceptionally high since the pressure required to produce desirable finishes is many times incapable of being accurately estimated because it depends on certain unpredictably varying factors inherent in asbestos-cement sheets. Since the variations occur during the actual processing and texture application the operator cannot so foresee the pressure and other requirements which will produce the desired texture and at the same time preserve all of the desired structural characteristics of the sheets.

A further problem which must be solved in an apparatus for applying a textured finish to wetformed material and which is to be of a sufficient speed to make the process substantially continuous is that of properly disposing of the liquid squeezed out of the material during the pressing operation. Not until material as hereinafter designated is actually Worked in a die of the character here described does one realize the necessity of evolving novel material-supporting devices which, as the material is rbeing textured, desirably permit the disposition of the liquid squeezed from the material. The use of a belt or a member for carrying the material into proper location with respect to the die is hereafter described, it being understood that the co-ordination of this belt or equivalent device and the structure thereof to achieve the desired disposition of the liquid is an important part of the completed'invention as it is hereinafter described and claimed.

It is one of the objects of the present invention to produce a textured iinish,l for instance @ne resembling the more or less weathered-appearing grain imitative of wooden shingles, on still wet and unset asbestos-cement sheets, of the type which are commonly produced by the well-known Hatscheck method, by means which involve a stationary horizontally supported die-plate against which the wet sheets, while suitably supported, are upwardly pressed by means of a heavy roller, so as to cause the transfer to the upper surface of the abastos-cement sheet of a negative replica of the conguration of the die-plate.

A further object of the present invention is to provide an apparatus comprising means for transferring a wet and limpid sheet of freshlyformed asbestos-cement to a position beneath a forming-die, and then, while the sheet is kept immovable, to compress said sheet linearly against the forming-die progressively from one side to the other until the desired design has been imparted thereto.

A further object of the invention relates to a travelling impression-producing carriage which moves first in one direction and then in the oppositeA direction beneath a properly supported sheet of asbestos-cement, said carriage being provided with a. heavy pressure-roller which is resiliently urged upwardly against the under side of such a sheet while means are also provided to absorb any liquid that is squeezed from the sheet during the operation.

Other objects will become apparent from the further description hereinbelow when considered in connection with the drawings in which:

Figures l and 1A, when considered together, comprise a complete plan View of an apparatus in which the invention is practiced, the view being in two portions because it is intended that Fig. 1A should be considered as an extension of Fig. 1; if the entire plan view were small enough to be placed on one sheet, the details would be unduly obscured;

Figs. 2 and 2A similarly are to rbe considered together as an elevational side view of the apparatus shown in Figs. 1 and 1A;

Fig. 3 is a plan view of that part of the apparatus illustrated in Figs. l, 1A, 2 and 2A which is hereafter designated as a movable truck or press-roller-carrying carriage frame, the dimensions utilized in this view being somewhat greater than those of the same parts in Figs. 1 and 2 and with certain parts omitted so as toclarify the showing;

Fig. 4 is an elevational side view of the rollercarriage shown in Fig. 3, the rail upon which the carriage travels; a portion of the rail-supporting beams being shown at the bottom of this figure;

Figs. 5, 6. 7 and 8 are vertical cross-sectional views, in an enlarged dimension, of various details of the press-roller, its associated devices, and the frame in which the latter are mounted, taken on the lines -5, 6--6, 1-1, and 8 8, respectively, of Fig. 4, the indicated sections being so taken and one or more observable elements being so omitted in these views the better to illustrate certain desired structural details;

Fig. 9 is an elevational sectional view taken on the line 9 9 of Fig. 2,

, Figs. 10, 11, 12 and 13 are purely diagrammatic elevational views of so much of the apparatus as is necessary to illustrate the process features of the present invention.

Referring first to Figs. 1, 1A, 2 and 2A, the apparatus comprises an elongated box-like frame built up from a plurality of structural members, the function of which latter and the manv, ner of joinder thereof with each other being sufciently clear from the drawing to render a more detailed description of this frame unnecessary. The frame comprises mounting means for a plurality of belt-supporting and driving rollers, two

sets'of co-operating rollers 2I-22 and 23-24 being situated at the left-hand or entry end of the machine and another set and 26 being situated at the right-hand or exit end thereof.

This belt is of a suitable wovenh or felted material, capable of absorbing water from the sheets being pressed, and generally is Wherever possible, brevity herein will be, se;

cured by omitting detailed explanation of various elements, the construction of which the drawing itself makes clearly apparent to those skilled in the art; for instance, it is not deemed necessary to describe the manner in which the just-referred-to belt carrying and driving rollers are journaled nor the manner in which the journals are mounted or supported on the various frame members. While this method of securing brevity will be employed throughout the specication, it is understood that applicant in no wise is intending thereby to describe less than a fully operative disclosure.

Positioned substantially centrally of the elongated box-like structure 20 is a die-mounting frame 28. The die proper 29 comprises a contoured plate, which latter may be secured to pri-V mary and secondary backing plates 33 and 3i (3| being fastened to the upper cross beams ofl frame 28) and is used to produ-ce the design which is to be impressed on the Work or material. Also as shown-in Fig. 9 longitudinally extending chain supporting and guiding beams 32--32 aren suspended from the transversely extending top cross beams of frame 28. In order to provide sucient rigidity, the frame 28 at the parts above the die 29 is surmounted by a heavy weight, such as a concrete mass I9, suiciently heavy to prevent upward displacement of the frame, and to furnish suflicient resistance to the action of the pressure-rollers.

The material, to the surface of which the die design is to be applied, is fed onto the web at the left or entry end of the machine. For purposes of illustration the material here considered is in the form of dat sheets of asbestos-cement S-S which has been formed in predetermined ingredient proportions of which the details are no part of the present invention or disclosure. After being formed, these sheets or slabs are fed over an entry table 33 onto the belt 21 and are carried into die-pressing position before the material so hardens as to be unreceptive to the die design.

During its travel along its upper flight, the belt 21 is supported on several sets of rollers. The first of these, from left to right, comprises rollers 34 mounted on -members 35435 which serve to support the belt from the driving roller 2i until it overlies rollers associated with the pressing instrumentality. At the right or delivery end of the apparatus the belt and whatever work is carried thereby are supported on a table 35, which latter is positioned above the highest position which the hereafter described press roller can assume. The belt is driven from the feedend of the machine, so that the belt will be slack where it supports the material to be impressed.

Movement of the belt 21 in the indicated direction carries the sheet forwardly (to the right,

Figs. 2.and 2A) until the slab is positioned directly beneath the die 29. The latter may be of any desired material and the design thereon may be either raised or depressed. This die is mounted in the'die frame 23 in such a way that it is firmly secured against movement when the hereinafter-referred-to pressures are set up as the slabs of material are pressed upwardly thereagainst.

During the time that the design is being imparted to the slab, the belt 21 ismaintained stationary. After the design has been made in the material, the belt is again progressed to move the slab out from under thel die and to the right, i. e., the belt moves over that portion of the frame which lis shown in Figs. 1A and 2A. The treated slab is thereafter removed from the belt, where the latter overlies table 36, by means, such as a, vacuum pick-up device, forming no part of the present invention and not here illustrated.

The means whereby the slab is pressed upwardly against the die comprise'the rotatable, toand-fro moving press-roller 31 which is operated beneath the belt to press the belt upwardly, wherefrom it follows that the slab supported on said belt beneath said die will also be pressed upwardly against the die with design-imparting pressure.

The press-roller 31 is supported in a movable pressframe or carriage, which latter is mounted on a truck having two pair of wheels. It should be immediately noted that the press frame or carriage is shown in full lines in Figs. 1 and 2 and in dotted lines in Figs 1A and 2A. The full line position illustrates the carriage in its extreme left-hand position and before it is moved to pass the roller 31 under the belt 21 to force a slab of material S-S upwardly against the die 29, whereas the dotted line position illustrates the position of the carriage in extreme right-hand position and after the press-roller` has carried out its pressing function in one direction. It also may similarly function yon its reverse travel as hereinafter more fully described.

The actual operation of the roller 31 in the performance of its pressing function will be described after'the various structural elements thereof and the manner in which they are co-ordinated have been detailed.

The press-roller 31 is journaled in journal brackets 38-38 which are in turn mounted on pivotally movable yoke side members 39-39.

v:sumaria Cross beams 40-40 extend between the free outer ends -of members 39-39 serving thereby to strengthen the roller-supporting yoke and also to provide mountings for spring abutment of thrust plates 4|-4ll which are welded to the top webs'of the beams 40-40. The yoke side members 39-39 are rigidly secured to depending members 42-42'which latter are pivotally mounted on downwardly `extending standards 43-43 welded to the bottom webs of main side frame beams 44-'44. The main side beams 44--44 are cross connected by end main frame beams 44a-44a, this main structure being designedly constructed so that it is much more rigid in a horizontal plane than otherwise. It may therefore be slightly twisted to insure the four wheels upon which the carriage is mounted solidly equally contacting the rigidly supported rails 13--14 upon which the carriage truck travels to and fro. This novel concept in the carriage structure insures an operative interfitting between the carriage, wheels and rails, and is accordingly hereafter covered in subcombination claims.

Expansion springs 45-45 areA each mounted (a pair thereof being-located near the outer end of each yoke frame member 39) around studs or elongated bolts 4'6, the upper ends of which latter pass through xed plates `41 and carry adjusting or take-up nuts 48 bearing against the upper surface of said plates 41. The bolts 46 have springthrust receiving heads 49 at their lowerends and lock nuts 50 at their upper ends.l The springs 45 are accordingly conned between said overhead plates 41 and the bolt heads 49 so that said springs are under constant compression, the amount of which latter can be adjusted by manipulation of nuts 48.

The plates 41-41 are welded to the top of the upper webs of short longitudinally-extending frame'members 5I, the latter extending in pairs between transverse frame .members 52 and 53. Said members 52 and 53 are secured to the underside of the main longitudinal frame beams 4444.

A jack screw 54 is threadedly seated in the lefthand cross member 40 at the free end of the roller carrying'yoke so that the head 55 thereof, because of its abutment against the bottom of fixed member acts as an adjustable stop to the-upward movement of the roller frame under the impetus of springs 45. The excess vertical extension of the working surface of said roller 31 can therefore be very carefully adjusted as dictated by the material to be printed or embossed and the pressure to be exerted, then 'desirably-predetermined by manipulation of the -nuts 48 andsubsequent locking thereof by lock 'nuts 5|).

The press-roller 31 is yaccordingly constantlyl 'spring-pressed upwardly to such extent that the upper' linearly defined operating portion of said press roller, as predetermined-by the justdescribed Yadju'stmentand before the truckv carries 'the roller beneath -the chais-normally slightly higher thanthefbottom faceof the die; in practice said* excess vertical dimension may illustratively be indicated as about lyto of an inch,

insufficient to appear lvisually inthe drawings.

Therefore, when this rolleris moved under' the the latter causesthe roller to be-,urged upwardly against the' belt 'and the slabfsupported thereon to the upper surface of the slab. This arrangement is an especially desirable one inthat it permits ready adjustment of the pressure with which the press-roll is urged upwardly to coin the'slab against the die. When it is realized that pressures of several thousand pounds are inherent in the here-described printing or material-coinlng process, the necessity of providing adjustments of relative simplicity is immediately apparent. For this reason the here-described spring-pressure procedure and the means for adjustably utilizing the same is deemed also worthy of sub-combination claims and the same are hereafter included. The use of a weight I9 to insure sufficient resistance has already been noted.

The truck or carriage frame upon which the i press-roller 31 is mounted runs on two pairs of wheels 5ft-56 and 51-51, mounted on the ends of two stationary axles 58 and 59, respectively. The latter are hung from pairs of depending U- shaped hangers 606|J, 60--60 and SI-BI, SI-EI with the closed part of the U passing under enlarged portions 58a on the axle 58. Two of Such pairs of hangers (5U- 50, 60-60) are located to the left of the press-roller 31 (one pair adjacent each end of axle 58) and the other pairs CGI-6| and GI-SI) being located to the right of pressroller 31.

rlhe U-shaped axle hangers draw the enlarged portions 59a of the axle 58 upwardly against short longitudinally extending structural members $2- 62 and 63-63, which latter extend between and are secured to transverse members 44a and 53. Plates 64 and 65 overlie the upper webs of the members 62 and 63. These plates serve as bearing surfacesfor the pull-up nuts 66 and 61 on the upper ends of the U-shaped hangers 62- 62 and 63-63.

idie', l it ymust. bev forced downwardlyrelative toA -"with'fsuicientfpressuretoimpart-the die designv A similar construction provides the mounting for the axle 59, i. e., transverse members 68 and 69 extend under and are secured to main side frame members 44-44 and short longitudinally extending members similar to 62-62 and 63--63 extend between said members 68-69, thereby to provideabutment against which the pairs of U- shaped hangers lil-6| can be utilized to secure enlarged portions on the axle member 59 l(similar to enlarged portions 58a on axle 58). The wheels 56--56 and 51-.51 are mounted on enlarged portions-56a-56a located at the upper ends of the axle member58, it not being deemed necessary to describe the roller-,bearing structure whereby said wheels are rotatably mounted on said portions 56a--56 a. 1 v

Chain sprockets 10-10 are fixed to inwardly extending portions of the wheels 56-56 andv 51-, 51 to drive the latter through .the agency of'a chain1l.

The wheels 5 6-,56and 5Fl-51' roll along'rails 13 and 14 mounted oni-beams; 15 and 1B, respectively, which lattenare lrigidly mountedon the floor ofI the structure housingof the herein ydescribed apparatus, andhen'ce serve to propel the .entire carriage, j including the roller 31. Sprockets 11.l and 18 are loosely rotatably mounted on the .shaft-ofthe .press-roll k31l and are ladapted Ato be operativelyA connected 'with said 'chain 1I. Roller 131 hence is not. positivelydriven.;4` Idler sprockets, andg8| are mounted `in the: positionsbest shown inFig.` 4: it is not deemed neces- ,saryto providea detailed description of the vjour- :nal structures upon whicnsaid sprockets Pare mounted. It is suicientftopoint outthai'fthe chain 1 I .is so threaded over .theso far: described sprockets that movement thereof causes the wheels 58 and 51 to rotate in such direction when thetruck carriage is moved to the right that the press roller will rotate in the opposite direction by virtue of its' contact with the under side of belt 21. By the same token, of course, rotation of said wheels to move the carriage to the left causes the press-roller to rotate in the opposite direction. The truck or carriage frame is moved to and fro along the. rails 13 and 14 by the operation of a motor 82 suitably structurally mounted on the carriage frame at the right thereof, the motor operating through a reduction gearing 83 to drive a sprocket 84 with which chain 85 is connected. Said chain 85 is connected to drive sprocket 86 which for convenience is mounted on the same member as sprocket 12, i. e., on the wheel 51. Accordingly, operation of motor 82 drives the wheels on which the roller carriage is mounted.

We have heretofore described the 4manner in which the belt 21 in its travel along its upper flight to the right is rst supported by rollers 34; Inasmuch as the belt preferably should be continuously supported until it overlies table 36, and inasmuch, further, as the truck carriage itself moves from the position shown in full lines in Fig. 2 to that shown in dotted lines shown in Fig. 2a. it is necessary to provide supporting rollers which are so associated with the roller-press carriage that said latter rollers can be continuously brought and maintained under the belt even though the said carriage moves as just described. Such belt support is provided rst by locating a series of rollers 81 on the carriage frame itself. These rollers are mounted in brackets 88flxedly positioned on longitudinally extending members 89 which in turn are mounted on.

members 98 supported on the main roller frame structure. The members 89 upon which the roller journal brackets 88 are mounted. are so positioned that said rollers 81 are progressively higher from either end of the carriage frame tward the press-roll position. This can be best seen in Fig. 4 where it will be observed that the rollers 81 are definitely so positioned that the belt 21 is carried higher at the point where the press-roller underlies the same than at other points. This avoids contact of rollers 81 with the belt during the coining operation.

To insure that the belt and the material which may be carried thereby is supported by rollers at those zones where neither the rollers 34, the

table 36, nor the rollers 81 on the carriage frame provide such support, further rollers 9| are provided, it being arranged ,that said rollers 9| are automatically placed beneath the belt in said zones which would otherwise contain no supporting rollers. These rollers 9| are mounted and carried by chains 92, the ends of which are attached one at the left-hand end of the carriage frame at S3 and the other at the right-hand end of the carriage frame at 94. The chain is geared to the sprockets 95 mounted at the left-hand end of the main frame, and the sprockets 96 mounted at the right hand end of said main frame. It will therefore be seen that as the carriage moves from right to left the chains 92 are drawn along by said carriage to place the rollers 9| beneath the belt at those points where said belt would otherwise not be supported. There need only be sufficient rollers on the chains 92 to support the belt, hence considerable portions of the belt will not have rollers thereon.

'I'his matter of support is a vital consideration when partially set material is supported on the belt for carriage beneath the die. Slabs such as are herein intended to be coined are often comapparatus frame in such manner that the carriage may move with respect thereto. The chains 92 are supported by and guided along the upper web of said members 32 in a manner best shown in Fig. 5. A raised bead 32a is formed on top of the upper web and thus serves as a guide to maintain the chain 92 as it is pulled back and forth by the carriage in proper alignment.

Accordingly, the belt 21 is well supported throughout its travel by suiciently closed spaced rollers. Having now described the instrumentalities which comprise an apparatus in which the novel method of producing a textured nish on a slab of material can be effected, reference may be had to the diagrammatic showings in Figs. 10 to 13 in connection with the following description of the cyclic operation of said apparatus to carry out said novel method.

In Fig. 10 a wet-formed asbestos-cement slab S-S is shown as having been moved by the belt 21 to a position directly under the die 29. The carriage carrying press-roller 31 is in its extreme left-hand position. The upper linear element of the roller is accordingly located a denlte predetermined verticalA distance above the under surface of the die. It will be understood that the movement of the belt to the position indicated, i. e., to locate a slab directly under the die, causes (through properly positioned limit switches) the belt to stop, and the belt and slab are accordingly maintained stationary until further automatic or manual manipulation again moves the belt 21. It will be observed that another slab is positioned on ythe belt to the leit of the die while a still further slab is positioned on the belt to the right of the die, the former slab (the one to the left) vbeing the next one to be located beneath the die, and the latter (the one to the right) being that slab which has just been embossed and has been moved from beneath the die.

The stoppage ofthe belt through properly, preferably manually, controlled electrical means initiates movement of the carriage to the right. Fig. ll illustrates Idiagrammatically the position of the press-roll 31 after it has been forced slightly downwardly in order to pass under the die and has correspondingly through its upwardly urged springs 45 been pressed upwardly against the underside of the belt. The carriage is driven through the heretofore described agency of the motor, and its vassociated chain drives to the right and the press-roller. while in its upwardly thrusting pressing position', thus rotates counterclockwise at the same speed as that in which the carriage is linearly progressed to the right, this being occasioned by its tight engagement with the belt 21. Fig. 12 illustrates the position of the operating instrumentalities after' the carriage has been driven to its extreme righthand position and hasv come to rest. When the 9 Fig. 12 position is reached by the carriage manual electric devices are brought into action `to cause the belt 21 again to travel to the right a suflicient distance to carry the just referred to press slab from beneath the die and to position the next succeeding slab thereunder. The carriage may then be moved to the left, thereby pressing the slab S-S just positioned. This causes the roller again to be depressed and to be thrust upwardly with sufcient pressure to impress the die design upon the upper surface of the slab resting beneath the die. Once again the direction of wheel rotation and the threading of the chains with the sprockets is such that the press-roller moves in a direction opposite to that in which the carriage is traveling, i. e., when the carriage is driven to the left, the press-roller operates in a clockwise direction, and as hereinbefore explained, it is, however, possible through simple reversing switches to the motor power leads to insure that the press-roller operates in the proper direction irrespective of the direction in which the carriage is driven. The coining operation on the return movement of the press-roll (i. e. to the left) is illustrated by Fig. 13. After the carriage reaches its extreme left-hand position, it is maintained stationary and once again the belt is moved to the right to place a fresh unpressed slab beneath the die after the belt has been thus moved. Finally, the cycle is automatically repeated.

It will be observed that because of the hereinbefore described dimensions and the manner in which the press-roll is moved under the die, an exceptionally heavy pressure is provided as the roll is depressed against the upwardly operating spring thrust which of course occurs immediately the roll contacts either the left-hand or the right-hand edge of the die, which is just before the roll contacts the belt directly under the edge of the slab. The automatic correlation of 'the linear movement of the truck With the rotating speed of the press-roll insures that no drag arises as the roll rolls along under the belt, and at the same time insures that no drag is communicated to the undersurface of the overlying slab with consequent distortion of the design which is being impressed upon the upper face of said slab.

For the sake of simplicity, the carriage and its operating mechanism is not shown in Figs.1,0 through 13, and the upward spring-thrust of the press-roll is -diagrammatically illustrated by the spring 45.

As the carriage moves back and forth beneath the weight-surmounted die, the rollers 9i will be alternately pulled into position from either end, so that ythe belt 21 is never without adequate support. The rollers 34, 81 and 9| are all preferably ball-bearing-mounted so as to cause as little friction as possible between the belt and therollers. Such bearings are not specifically illustrated as their construction is well known.

Under certain circumstances it may be desirable to effect the coining operation only when the roller 31 is moving in one direction. Therefore, upon its return movement the roller may be permitted merely to press the belt 21 against the die. This will not injure the die, and may serve a useful function in squeezing any excess water out of the material of which the belt may be made. Such an operation is to be considered as within the process claims of the present application.

In essence the apparatus provides means for transporting a slab of coinable material into coining position, means for exerting heavy linear pressure progressively upon a supported slab of the material whereby it will be pressed upwardly against a coining-die, and means for bringing supporting rollers under the belt whenever the press-roll carriage is not directly beneath the belt so as to permit the rollers 81 on the carriage to support the belt.

While the apparatus has been described in considerable detail in order to make its operation fully understood, it will be evident that considerable modification is possible, and that such equivalents as will be familiar to the art of machine-construction are to be considered as within the general scope and purview of the following claims, in which the inventor claims as his in ention:

1. A /machine for impressing a design into the surface of a. plastic impressionable sheet of material which comprises av beltl conveyor for said sheet, a die suspended above said belt, a springbiased pressure-imparting roller mounted for reciprocal movement beneath said belt and adapted to press said belt and the thereupon supported sheet against said die, and means for reciprocally moving said roller.

2. A machine for` impressing a design into the surface of a plastic impressionable sheet of material which comprises a belt conveyor for said sheet, a 4die suspended above said belt, a springbiased pressure-imparting roller mounted for reciprocal movement beneath said belt and adapted to press said belt and the thereupon supported sheet against said die, means for reciprocally moving said roller, and means, connected with said last-mentioned means, for positioning beltsupporting means under said belt.

3. In a machine of the character described, the combination of a frame, rollers carried by said frame, a belt movable upon and supported by said rollers for a portion only of its travel; a set of spaced-apart rails beneathsaid belt;-awheeled carriage supported upon and movable on said rails; a heavy pressure-roller supported upon said carriage and means thereon for biasing said pressure-roller in an upward direction; a coining-die supported above said belt; a, heavy mass in contact with said die; and means for reciprocatably moving said carriage upon said rails with the pres- 50...

sure-roller in intimate contact with the under surface of said belt, whereby said belt and slabs of impressionable plastic material carried theretious material comprising a horizontally supported heavily weighted stationary die; linear transporting means positioned beneath but close to said die for transporting one of said slabs into a position immediately below said die; means for applying linear pressure progressively against the underside of said transporting means whereby t0 press the slab supported vthereby strongly against said die so as to impress the slab with a nega.- tive replica thereof; means associated with said last-mentioned means to position a plurality of supporting rollers under said supporting means to support the said supporting means; means for moving said transporting means; and means for spring-biasing said linear pressure applying means upwardly against said transporting means and the slab supported thereon.

5. A machine for impressing designs into the surface of freshly-formed slabs of unset cementitious material comprising an elongated framesitioned beneath said belt at points not occupied work; a movable transporting belt theraon comby said carriage.

posed of a moisture-absorbing and moisture-per- WILUAM L, NELSON, meable material; means for intermittently moving said belt; a coining-die supported immedi- 5 REFERENCES CITED ately above the Central Portions 0f Said belt? a The following references are of record in the heavy mass of material in contact with the back v side of said die; means for feeding slabs of unset me of this pd'tent cementitious material onto said belt; means, po- UNITED STATES PATENTS sitioned beneath said belt and reciprocally mov- 10 Number Name Date able thereunder, for pressing said belt against said 1,321,384 Mattison, Jr. Nov. 11, 1919 die, said means comprising a press-roller and 1,726,541 Cole Sept. 3, 1929 n movable caiage assigiated therewith and means 2,006,528 Wa1per Ju1y 2, 1935 for alterna ly mo said carriage to ther-ight and to the left; means for arresting the travel 15 FOREIGN PATENTS oi' said belt during the movement of said car'` Number Country Date riage; and chain-supported roller-means con- 22,409 Great Britain 1914 nected with said carriage and adapted to be po- 

